Search for disappearing tracks in proton-proton collisions at $\sqrt{s} = 13\,\mathrm{TeV}$

A search is presented for long-lived charged particles that decay within the CMS detector and produce the signature of a disappearing track. A disappearing track is an isolated track with no associated hits in the muon detectors, little or no energy in associated calorimeter deposits, and missing hits in the outer layers of the silicon tracker. The search uses $38.4\,\text{fb}^\text{$-$1}{}$ of proton-proton collision data collected by the CMS detector in 2015 and 2016, at a center-of-mass energy of $13\,\text{TeV}{}$ at the CERN LHC. The results of the search are interpreted in the context of anomaly-mediated supersymmetry breaking. The observation is consistent with the background-only hypothesis, and limits are set on the product of the cross section of direct chargino production and branching fraction to a neutralino and a pion in terms of the chargino mass and lifetime. At $95\%$ confidence level, charginos with masses less than $715\,\text{GeV}{}$ are excluded for a lifetime of $3\,\text{ns}{}$.